How to release an NSMutable Array which we need to use in return statements

Question

IM USING SQLITE DATABASE for my iPhone app

In my app in data base to retried the content from the database i used an array and i return this array in a database method for select statement,

for this purpose i allocate an array and i need to release the array,

NSMutableArray *allContacts = [[NSMutableArray alloc] init];
 return allContacts;

if i release an array how sh'd i used in return statement

viceversa if i tried to release after return (we can do anything after return)

Any solution please....

How should we use auto release NSMutable array

//Select statement for contacts
//==================================
+ (NSMutableArray*) selectAllContactsFromDB
{
      NSString *DBPath = [self copyDBFile];
      sqlite3 *contactsDB = nil;
      sqlite3_stmt *statement = nil;
      NSMutableArray *allContacts = [[NSMutableArray alloc] init];

      if (sqlite3_open([DBPath UTF8String], &contactsDB) == SQLITE_OK)
      {
            NSString *query = [NSString stringWithFormat: @"SELECT ROWID, NAME, MOBILE,  FROM CONTACTINFO"];
            if(sqlite3_prepare_v2(contactsDB, [query UTF8String], -1, &statement, NULL) == SQLITE_OK)
            {
                  while (sqlite3_step(statement) == SQLITE_ROW)
                  {
                        Contact *contact = [[Contact alloc] init];
                        contact.rowid = sqlite3_column_int(statement, 0);
                        contact.name = [NSString stringWithUTF8String:(const char*) sqlite3_column_text(statement, 1)];
                        contact.mobile = [NSString stringWithUTF8String:(const char*) sqlite3_column_text(statement, 2)];


                        [allContacts addObject:contact];
                  }
            }
            else {
                  NSLog(@"Statement not prepared");
            }
      }
      [DBPath release];
      return allContacts;
}

Answer 1

When you return an allocated object from a method pass it as an autoreleased object.

return [allContacts autorelease];

When you get an autoreleased object you need to retain it for further use:

So change the calling method like;

NSMutableArray *temp = [[YourClass selectAllContactsFromDB] retain];

Answer 2

try like this

NSMutableArray *allContacts = [[[NSMutableArray alloc] init] autorelease];

and also like this..

return [allContacts autorelease];

Answer 3

You can write return statement return [allContacts autorelease]; OR you can use ARC in your project.

Answer 4

You will have to use autorelease :

return [allContacts autorelease];

This way il will be released the next time the autorelease pool will be flushed. And you have followed the golden rule : For each alloc, copy or retain, you must have a release or autorelease.

Answer 5

use ARC(Automatic Reference Counting) or you have a property as a mutuable array and just return the array...

to get u started on ARC, watch this: http://www.youtube.com/watch?v=FxuI4e_Bj58